Meter-kilogram-second units

SI Units—The International System of Units as defined by the General Conference of Weights and Measures in 1960. These units are generally based on the meter/kilogram/second units, with special quantities for radiation including the becquerel, gray, and sievert. 

Joule The meter-kilogram-second unit of work or energy, equal to the work done by a force of one Newton when its point of application moves through a distance of one meter in the direction of the force equivalent to 107 ergs and one watt-second. 

The official set of units that physicists and chemists use is the International System of Units, or SI units. The letters SI stand for Systeme Internationale, the French name for the set of units. In this system there are seven base units. The unit of length is the meter (m). The unit of mass is the kilogram (kg). The unit of time is the second (s). The unit of temperature is the kelvin (K). The unit of electric current is the ampere (A). The unit of luminous intensity is the candela (cd). The unit for the amount of a substance is the mole (mol). The SI units are called MKS (meter-kilogram-second) units. Prior to 1961, most chemists and some physicists used cgs (centimeter-gram-second) units, but we now use SI units to avoid confusion. 

A dual system of units is used in this book, with the primary system being the the International System of Units (SI units, or meter-kilogram-second units). Because of a tradition of using cgs (centimeter-gram-second) units in this field, especially in the United States, cgs imits are included in square brackets, and some equations and most examples are presented both ways. 

Contacting power is variously expressed in units of MJ/1000 m3 (SI), kWh/1000 m3 (meter-kilogram-second system), and hp/(1000 ft3/min) (U.S. customary). Relationships for conversion to SI units are... 

In the present book, for magnetism we use the SI unit that is based on the MKS A (meter, kilogram, second, ampere) system. In accordance with that, the tesla (1T = 10" gauss) was presented as the magnetic unit in Chapter 17 (see Fig. 17.10a and b). It is useful to know both the SI and Gaussian systems and be able to convert between them. Thus, when one attempts to solve a magnetics problem, to avoid errors one is well advised to stick to a single convenient unit system. A useful conversion table of... 

SI units International system of units based on the meter, kilogram, second, ampere, kelvin, candela, mole, radian, and steradian. 

The basic unit of radioactivity is the curie, Ci. One curie is the amount of radioactive material that emits particles at a rate of 3.7 X 1010 disintegrations per second (dps), or 2.2 X 1012 min-1 (dpm). Amounts that large are seldom used in experimentation, so subdivisions are convenient. The milli-curie (mCi, 2.2 X 109 min-1) and microcurie (yu,Ci, 2.2 X 106 min-1) are standard units for radioactive measurements (see Table 6.2). The radioactivity unit of the meter-kilogram-seconds (MKS) system is the becquerel (Bq). A becquerel, named in honor of Antoine Becquerel, who studied uranium radiation, represents one disintegration per second. The two systems of measurement are related by the definition 1 curie = 3.70 X 1010 becquerels. Since the becquerel is such a small unit, radioactive units are sometimes reported in MBq (mega, 106) or TBq (tera, 1012). Both unit systems are in common use today, and radioisotopes received through commercial sources are labeled in curies and bequerels. 

The metric system consists of a base unit and (sometimes) a prefix multiplier. Most scientists and healthcare providers use the metric system, and you are probably familiar with the common base units and prefix multipliers. The base units describe the type of quantity measured length, mass, or time. The SI system is sometimes called the MKS (meter, kilogram, second) system, because these are the standard units of length, mass, and time upon which derived quantities, such as energy, pressure, and force, are based. An older system is called the CGS (centimeter, gram, second) system. The derived CGS units are becoming extinct. Therefore, we will focus on the MKS units. 

Still, units can be a nuisance. One difficulty is that much serious theoretical work is still done in centimeter-gram-second (cgs) or "Gaussian" units such is the case with the Level 3 derivations in this text. Most students learn applications in meter-kilogram-seconds (mks) "SI" or "Systeme International" units. Happily, practical formulae for... 

Example In the MKSA (meter-kilogram-second-ampere) system of units, length, mass, time and current are the fundamental measurables, symbolically represented by L, M, T, and I. Therefore we say that velocity has the dimensions LT. Energy has the dimensions ML2T2. 

MKSA. The system of physical units based on the fundamental metric units meter kilogram, second and ampere. 

The value of K may be obtained from Figure 3.7 (Roberson et al., 1988). All units should be in MKS (meter-kilogram-second) system. 

The 1,000 in the denominator is the mass density of water in kg/m at the temperature of 4°C used as the reference temperature in the definition of specific gravity. All units in this equation must be in the mks (meter-kilogram-second) system. 

Williams, P. J. le, B. (2004). Meters, kilograms, seconds, but no bomb emits. Azero tolerance approach to units. (With apologies to Lynne Truss). Limnol. Oceanogr. Bull. 13(2), 29—32. 

The SI is constructed from seven base units for independent quantities (meter, kilogram, second, ampere, kelvin, mole, and candela) plus two supplementary units for plane and solid angles (radian and steradian). Most physicochemical measurements can be expressed in terms of these units. 

The International System of Units (Systeme International SI) was adopted in 1960 by the General Conference of Weights and Measures as a coherent system based on seven basic units the meter, kilogram, second, ampere, kelvin, candela, and mole. In human medicine, the system has not been adopted universally. 

International System of Units (SI) - The unit system adopted by the General Conference on Weights and Measures in 1960. It consists of seven base units (meter, kilogram, second, ampere, kelvin, mole, candela), plus derived units and prefixes. [1]... 

---